需要js手动设置inpu的indeterminate属性为true
input:indeterminate::after {
content: "";
display: block;
height: 3px;
7px;
margin: 40% auto;
background-color: #395acc;
}
input:checked,
input:indeterminate,
input:checked::after {
background-color: #395acc ;
border: 1px solid #395acc ;
}